Identify which of the following are characteristics of cyanobacteria.
check all that apply:

gram-negativegram-negative

gram-positivegram-positive

anoxygenic phototrophs

anoxygenic phototrophs

oxygenic phototrophs

oxygenic phototrophs

always unicellular

always unicellular

may possess nitrogenase, an enzyme that fixes n2 into organic compounds

may possess nitrogenase, an enzyme that fixes n2 into organic compounds

some species may form filamentous multicellular associations

some species may form filamentous multicellular associations

may possess nitrogenase, an enzyme used to produce atp from ammonia

Explanation:

Cyanobacteria, also known as blue-green algae, are organisms that obtain their energy through photosynthesis.

1. Cyanobacteria are considered gram-negative. However, studies show that their envelope exhibit some gram-positive characteristics.

2. Cyanobacteria and other organisms, such as algae, use photosynthesis take the energy from light (the sun), which results in the generation of oxygen as a byproduct. Therefore, they are oxygenic phototrophs.

3. Anoxygenic organisms don't generate oxygen as a byproduct and use hydrogen sulfide rather than water. Although most cyanobacteria are oxygenic phototrophs, few species, such as Oscillatoria limnetica, have developed environmental adaptations such as the ability of sulphide-dependent anoxygenic photosynthesis (Hamilton, 2019).

4. and 5. Some species of cyanobacteria form filamentous multicellular associations (some are unicellular species) and synthesize the enzyme nitrogenase to fix molecular nitrogen.

the statement is true

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.